1. Field of the Invention
The present invention generally relates to ski equipment. More particularly, this invention relates to a ski boot and ski boot binding system that provides, preferably in combination, a toe release system for reducing the risk of knee injuries and an ankle-flex steering system for increasing turn performance.
2. Description of the Related Art
The stiffness of modern ski boots has drastically reduced the incidence of ankle injuries. For ski boots of the clam shell-type (having front and rear cuffs pivotably coupled to a foot shell), this stiffness is the result of permitting only limited lean adjustment in the forward direction and essentially none in the rearward direction. While protecting the ankle, boot stiffness places greater loads on the knee, such that sprains and tears of the anterior cruciate ligament (ACL) are now a relatively common type of injury associated with downhill skiing. One particular type of ACL injury is termed the “phantom foot injury” and involves the tail of the ski, which points in the opposite direction of the skiers” foot. A phantom foot injury occurs when the tail of the ski acts as a lever to apply (through the rigid rear cuff of the boot mounted to the ski) a forward force on the lower leg. Such a situation occurs when the skier is off-balance rearward, with hips below the knees in a squatting position. In this position, the lack of flexing of the boot rear cuff results in the tail of the ski being forced downward. The tendency is for an edge of the ski tail to “catch,” causing the ski and boot, and therefore the lower leg of the skier, to twist under load.
Various approaches have been proposed for avoiding this type of injury, notable examples of which include commonly-owned U.S. Pat. Nos. 4,880,251, 5,020,822, 5,026,087, and 5,412,883. The avoidance of phantom foot and ACL injuries is also the subject of U.S. Pat. No. 5,107,608 to Kreitenberg and U.S. Pat. No. 6,131,313 to Pierce et al. Each of these solutions generally involves releasing the rear cuff from the front cuff, allowing increased rearward motion of the skier's lower leg relative to the ski in order to reduce the load on the knee. While this type of safety feature is a significant improvement over conventional ski boots, further improvements are still desired to provide greater safety and comfort to skiers.
In addition to safety, comfort and performance are also of great interest to downhill skiers, particularly those who ski competitively. Commonly-owned U.S. Pat. Nos. 4,880,251, 5,020,822, 5,026,087, and 5,412,883 offer significant improvements in both comfort and performance, including a flexible toe that makes walking considerably easier and safer, and the ability to adjustably cant the boot relative to its binding (and therefore the ski). As with the issue of safety, further improvements in comfort and performance are also continuously sought by the skiing industry.